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Food, which comes from animals and plants, is made up of some proteins, sugars, fats and other nutrients of which all-living tissues consist, including those of the human body.

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Introduction and Hypothesis Food, which comes from animals and plants, is made up of some proteins, sugars, fats and other nutrients of which all-living tissues consist, including those of the human body. As consumers we are interested to know the amount of sugar (glucose) present on different foods that we use in our every day life. Therefore an experiment is going to be carried out to find the glucose concentration in different types of foods. On this experiment we decided to test five different types of food, which are: apples, oranges, lemons, carrots and potatoes. We can divide these in two groups: a) Fruits, b) Roots The reason we are testing these roots and fruit is the existent suspicion that there is some glucose present on some of them and also because they are more suitable for the experiment as they are easy to find and inexpensive. To make a start, first of all the presence of a basic idea is required for the function of glucose: Glucose is monosaccharide sugar with the empirical formula C6H12O6. This carbohydrate occurs in the sap of most plants and in the juice of grapes and other fruits. Glucose is a normal component of animal blood; it thus requires no digestion prior to absorption into the bloodstream. Glucose is a ready source of energy, since its carbon atoms are easily oxidized (burnt) to form carbon dioxide, releasing energy in the process. However, unlike other hydrocarbon fuels, which are insoluble in water, the numerous OH groups in glucose allow it to readily hydrogen bond with water molecules, so making it highly soluble in water. This allows the glucose fuel to be transported easily within biological systems. Because glucose is found in ripe fruits, the nectar of flowers, leaves, sap and blood, over the years it has been given various common names, such as starch sugar, blood sugar, grape sugar and corn sugar. ...read more.


they are placed into the test-tube rack using a test-tube holder and they are left to cool in the air (this might need a over night settling as the solution have to be fully settled). At this point what we have is 6-test tubes with glucose solution of known concentration label in appropriate way and having different colours. We also have 5-test tube labelled on the basis of food solution they contain and different colour one from another. The last step to be followed is the measurement of the colour of each solution with a colorimeter. We are using a colorimeter to measure the colour because is the most accurate method to obtain data for each colour as well as find the right amount of glucose present. This can be don after all the solution has settle so that nothings affects the reading. Test first the colour of distilled water, which is colourless solution meaning no data should be read. We are doing this just so that there will be no mistake with the equipment used and also to have an expectation or understanding of the date data that will be obtain from the coloured solutions. Now a small amount of each coloured glucose solutions is placed on the small containers of the colorimeter and the corresponding readings are recorded on a data table (the table is to be named glucose colour data or better table 1.1). Plot this reading into a graph, which will give the outcall calibration curve. This graph will have on the x-axis a range of readings of the colours of the glucose and on the y-axis a range of glucose concentrations. ATTENTION: The measurements for the colour of each glucose solution are repeated for at least 3 times so that accurate result can be obtained. It might be the case that average readings have to be calculated if the data various from one measurement to another. ...read more.


difference in the colour change, especially because the typical amount of benedict's solution used in biological test is 2 to 5 drops. We tried to eliminate some of uncertainties of our lab with our controls; however, there were some problems that we did not foresee. One was the fact that there was a reasonable amount of precipitate, which did not settle easily. Therefore we had to leave the solutions over night for the precipitate to sink to the bottom of the test tube before we took any readings on the colorimeter. Because as we know as we know the colorimeter measures only the light intensity on solution and not precipitates. Another was the fact that to estimate the percentage of the glucose present on the food samples, we had to use to the correction curve drown from the result of the standard glucose solutions which we aren't shore if it was drown correctly. And also as we sad above to recognise the colour difference between the standard glucose solution and the food sample we had to use the colorimeter. Therefore there is a percentage error in this case as we cannot be 100% shore if the food solution was completely settle for the colorimeter to read the exact corresponding value for the light intensity passing through the colour mixture. There were also many opportunities for human errors. No matter how careful we were, there is always the chance that we added a couple extra drops of Benedict's solution in one test tube, or a couple drops more of a certain foods juice or standard glucose solution in the another. To improve upon our experiment or to extend its usefulness, experiment can be repeated more often with further work on to greater variety of foods and to be taken average readings making the experiment more accurate. As I mentioned before, it would add credibility to our date if more trial are carried out and if only two ore three drops of Benedict's solution is used ...read more.

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